Get values from a checkbox list

I have a page showing a list of movies previously inserted by the user and I want to make an action for removing the movies from the arraylist in which they are.

My mostraElenco.jsp is

My struts-config is

And my RemoveMovieAction.java is

ListaFilm is made like this

what i get when i try to access to mostraElenco.jsp is

I know i shouldn't do this

since ListaFilm is static, I tried to do
ArrayList<Movie> filmDaRimuovere = (ArrayList<Movie>) form;
but I get errors since the compiler tells me that it can't convert from ActionForm form to ArrayList

1) The message error is obvious. It cannot find the getter for "listMovie". I don't even see where you have "listMovie" defined. Is it defined and made public in "ShowElencoAction"?
2) You don't do an array of forms. You need to do an array of "Movie".